code: def _upstream_uri(self, party_id):
      host = self._mq.route_table.get(party_id).get("host")
      port = self._mq.route_table.get(party_id).get("port")
      upstream_uri = f"amqp://{self._mq.union_name}:{self._mq.policy_id}@{host}:{port}"
      return upstream_uri
  
imports: import json
  from logging import getLogger
  from typing import List, Optional
  from fate.arch.federation.api import PartyMeta
  from fate.arch.federation.message_queue import MessageQueueBasedFederation, Party
  from ._mq_channel import MQChannel
  from ._rabbit_manager import RabbitManager
label_desc: Use image node_id 9 for calling the RabbitmqFederation obj's underlying member method code with example usage: obj._upstream_uri(party_id) and returns: upstream_uri